| 摘要 |
PURPOSE:To obtain a device of a reduced number of pins when integrating by amplifying a chrominance signal having a carrier wave of the first frequency by an automatic gain control amplifier, mixing the frequency of the amplified chrominance signal with a comparison signal of the second frequency by a multiplier to output to a band pass filter. CONSTITUTION:A chrominance signal having a carrier wave of 2.56MHz inputted to an input terminal 1 is converted to a chrominance signal having the carrier wave of 2.56MHz of a fixed amplitude level by an automatic gain control amplifier 7 in accordance with the amplitude level of an output signal from a switch 9. This chrominace signal is frequency mixed with a comparison signal of the frequency centering 6.14MHz from a voltage control oscillator 3 by a multiplier 2 to output as the chrominance signal in which the frequency is converted to 6.14MHz+ or -2.56MHz to an input terminal 4 for BPF. Thereby, since the output signal from a band pass filter 5 becomes to the chrominance signal having the carrier waves of 3.58MHz restricted to the fixed amplitude level, it can be used as a signal for a signal processing in a later step as it is. Therefore, when integrating, the terminal of the signal processing in the later step is not required.
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